U.S. patent number 7,440,286 [Application Number 11/927,549] was granted by the patent office on 2008-10-21 for extended usb dual-personality card reader.
This patent grant is currently assigned to Super Talent Electronics, Inc.. Invention is credited to Siew S. Hiew, Abraham C. Ma, Nan Nan, Jim Chin-Nan Ni.
United States Patent |
7,440,286 |
Hiew , et al. |
October 21, 2008 |
Extended USB dual-personality card reader
Abstract
A dual-personality card reader system supports both USB and
micro-SD devices using a card reader and an extended 9-pin USB
socket. The card reader includes a PCBA having four standard USB
metal contact pads and several extended purpose contact pads
disposed on an upper side, components and IC chips covered by a
molded case on a lower side, a molded lead-frame connector mounted
on the PCBA and including five forward-facing extended purpose pins
and eight rear-facing micro-SD connector pins that communicate with
the PCBA through the extended purpose contact pads, and a housing
including a slot for receiving a micro-SD card such that it
communicates with the PCBA through the micro-SD connector pins. The
extended 9-pin USB socket includes standard USB contacts and
extended use contacts that communicate with the PCBA through the
standard USB metal contacts and forward-facing extended purpose
pins. The PCBA includes dual-personality electronics for SD/USB
communications.
Inventors: |
Hiew; Siew S. (San Jose,
CA), Nan; Nan (San Jose, CA), Ni; Jim Chin-Nan (San
Jose, CA), Ma; Abraham C. (Fremont, CA) |
Assignee: |
Super Talent Electronics, Inc.
(San Jose, CA)
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Family
ID: |
39187522 |
Appl.
No.: |
11/927,549 |
Filed: |
October 29, 2007 |
Prior Publication Data
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Document
Identifier |
Publication Date |
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US 20080067248 A1 |
Mar 20, 2008 |
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Related U.S. Patent Documents
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Application
Number |
Filing Date |
Patent Number |
Issue Date |
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11773830 |
Jul 5, 2007 |
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11112501 |
Apr 21, 2005 |
7269004 |
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11868873 |
Oct 8, 2007 |
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Current U.S.
Class: |
361/737; 361/715;
361/727 |
Current CPC
Class: |
G06K
19/077 (20130101); G06K 19/07732 (20130101); G06K
19/07741 (20130101) |
Current International
Class: |
H05K
7/14 (20060101) |
Field of
Search: |
;361/737,727,683-686,715
;439/607,374,79,379,610,680 |
References Cited
[Referenced By]
U.S. Patent Documents
Other References
USB FlashCard "Main Body Dimensions", "Top View", "Bottom View" Web
pages, Lexar, 2004, 3 pages. cited by other .
USB `A` Plug Form Factor, Revision 0.9, Guideline for Embedded USB
Device Applications, Nov. 29, 2004, 4 pages. cited by
other.
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Primary Examiner: Bui; Hung S
Attorney, Agent or Firm: Bever, Hoffman & Harms, LLP
Bever; Patrick T.
Parent Case Text
RELATED APPLICATIONS
This application is a CIP of U.S. patent application for "Molding
Methods To Manufacture Single-Chip Chip-On-Board USB Device" U.S.
application Ser. No. 11/773,830, filed Jul. 5, 2007, which is a CIP
of U.S. patent application for "Low-Profile USB Device", U.S.
application Ser. No. 11/112,501, filed on Apr. 21, 2005 now U.S.
Pat. No. 7,269,004.
This application is also a CIP of U.S. patent application for
"Extended USB PCBA And Device With Dual Personality" U.S.
application Ser. No. 11/868,873, filed Oct. 8, 2007.
This application is also related to co-owned U.S. Pat. Nos.
7,021,971, 7,108,560, 7,125,287, and 7,104,848.
Claims
The invention claimed is:
1. An extended Universal-Serial-Bus (USB) dual-personality card
reader having a connector plug that is compatible with both a
standard USB socket and an extended multiple pin USB socket having
both four standard USB contacts and a plurality of dual-personality
contacts, said card reader comprising: a printed circuit board
assembly (PCBA) including: a printed circuit board (PCB) having
opposing first and second surfaces, a plurality of metal contacts
disposed on the first surface of the PCB, the plurality of metal
contacts including four standard USB contact pads and a plurality
of extended purpose contact pads, a dual-personality communication
integrated circuit (IC) mounted on the second surface, and a
plurality of conductive traces formed on the PCB such that each
conductive trace is electrically connected between at least one of
said plurality of metal contacts and said a dual-personality
communication IC; a plurality of first extended-use contact
structures and a plurality of second extended-use contact
structures disposed on the first surface of the PCB such that the
first extended-use contact structures are disposed between the
second extended-use contact structures and the standard USB contact
pads, wherein each of said first and second extended-use contact
structures is connected to a corresponding contact pad of said
plurality of extended purpose contact pads; and an external housing
mounted over the first surface of the PCB, wherein said standard
USB contact pads and said plurality of first extended-purpose
contact structures are disposed outside of said housing and form
said connector plug arranged such that each of said standard USB
contact pads is contacted by a corresponding standard USB contact
of said extended multiple pin USB socket and each of said first
extended-purpose contact structures is contacted by a corresponding
dual-personality contact of said extended multiple pin USB socket
when said connector plug is inserted into said extended multiple
pin USB socket, and wherein said external housing includes a socket
for detachably receiving a flash memory device such that each
contact pad of the flash memory device contacts a corresponding one
of said second extended-use contact structures, thereby enabling
communication between said flash memory device and said
dual-personality communication IC.
2. The card reader according to claim 1, wherein the plurality of
second extended-use contact structures include eight first contact
pins, each said first contact pin being attached to said
corresponding contact pad of said plurality of extended purpose
contact pads, and wherein said socket defines an opening sized to
receive a micro Secure-Digital (micro-SD) card such that each of
eight contact pads of said micro-SD card contacts a corresponding
one of said eight first contact pins.
3. The card reader according to claim 2, wherein the plurality of
first extended-use contact structures comprises five second metal
spring structures soldered to said corresponding contact pad of
said plurality of extended purpose contact pads, whereby the
connector plug comprises said five second metal spring structures
and said four standard USB contact pads.
4. The card reader according to claim 3, wherein the eight first
metal spring structures and the five second metal spring structures
are fixedly connected to a molded plastic body.
5. The card reader according to claim 1, further comprising a
molded lead-frame connector including a plastic molded body having
a front edge, an opposing rear edge, and a bottom surface extending
between the front and rear edges, wherein said first
extended-purpose contact structures comprise forward-facing pins
extending from the front edge of the plastic molded body, and
wherein each forward-facing pin includes an associated first
contact pad disposed on said bottom surface, wherein said second
extended-purpose contact structures comprise rear-facing pins
extending from the rear edge of the plastic molded body, and
wherein each rear-facing pin includes an associated second contact
pad disposed on said bottom surface, and wherein each said first
and second contact pads is soldered to a corresponding contact pad
of said plurality of extended purpose contact pads.
6. The card reader according to claim 5, wherein each of said
forward-facing pins further includes a step portion extending from
said associated first contact pad into said plastic molded body,
and wherein each of said rear-facing pins further includes a step
portion extending from said associated second contact pad into said
plastic molded body.
7. The card reader according to claim 5, wherein each of said
forward-facing pins and said rear-facing pins comprises a curved
spring section.
8. The card reader of claim 5, wherein the external housing
comprises: a first housing portion defining a trough for receiving
said PCBA such that said molded lead-frame connector extends above
the trough, and a second housing portion that attached to the first
housing such that the second housing portion covers said second
extended-use contact structures, wherein said second housing
portion includes a rear wall defining a slot opening for receiving
said flash memory device; and wherein said card reader further
comprises a metal head cover attached to said first housing portion
and defines a front opening for accessing said standard USB contact
pads and said first extended-purpose contact structures.
9. The card reader of claim 5, wherein the external housing
comprises: a main housing portion defining chamber for receiving a
rear portion of said PCBA, wherein a back wall of said main housing
portion defines a slot for receiving said flash memory device; and
a tray extending from a front opening of said main housing portion,
said tray supporting a front portion of said PCBA, and wherein said
card reader further comprises a metal head cover attached to said
main housing portion and surrounding said tray, said metal head
cover defining a front opening for accessing said standard USB
contact pads and said first extended-purpose contact
structures.
10. The card reader of claim 5, wherein the external housing
comprises: a main housing portion including walls defining a
relatively wide chamber for receiving a rear portion of said PCBA,
and a relatively narrow plug portion integrally molded to the walls
for receiving a front portion of said PCBA, and a tray disposed in
the plug portion of the main housing portion, said tray supporting
a front portion of said PCBA, and wherein said plug portion defines
a front opening for accessing said standard USB contact pads and
said first extended-purpose contact structures.
11. The card reader of claim 5, wherein the external housing
comprises a main housing portion including walls defining a chamber
for receiving a rear portion of said PCBA, and a front tray
structure for receiving a front portion of said PCBA such that said
standard USB contact pads and said first extended-purpose contact
structures are exposed over said front tray structure.
12. The card reader according to claim 1, wherein said PCBA further
comprises at least one surface-mount-type passive components,
soldered to the second surface, and wherein said dual-personality
communication integrated circuit (IC) comprises a die that is
connected to said plurality of traces by bond wires.
13. The card reader of claim 12, further comprising a single-piece
molded casing formed on the second surface of the PCBA such that
said dual-personality communication integrated circuit (IC) and
said surface-mount-type passive components are covered by said
molded casing, and such that substantially all of the first surface
of the PCB is exposed.
14. The card reader of claim 1, wherein said PCBA further comprises
one or more flash memory circuits, and said dual-personality
communication integrated circuit (IC) includes means for
transmitting data between the flash memory circuits and said host
by way of said standard USB contact pads.
15. An extended Universal-Serial-Bus (USB) dual-personality card
reader having a connector plug that is compatible with both a
standard USB socket and an extended multiple pin USB socket having
both four standard USB contacts and a plurality of dual-personality
contacts, said card reader comprising: a modular core component
including: a printed circuit board assembly (PCBA) including: a
printed circuit board (PCB) having opposing first and second
surfaces, a plurality of metal contacts disposed on the first
surface of the PCB, the plurality of metal contacts including four
standard USB contact pads and a plurality of extended purpose
contact pads, a dual-personality communication integrated circuit
(IC) mounted on the second surface, and a plurality of conductive
traces formed on the PCB such that each conductive trace is
electrically connected between at least one of said plurality of
metal contacts and said a dual-personality communication IC; a
molded lead-frame connector including a plastic molded body having
a front edge, an opposing rear edge, and a bottom surface extending
between the front and rear edges, a plurality of forward-facing
pins extending from the front edge of the plastic molded body, and
a plurality of rear-facing pins extending from the rear edge of the
plastic molded body, wherein each forward-facing pin includes an
associated first contact pad disposed on said bottom surface,
wherein each rear-facing pin includes an associated second contact
pad disposed on said bottom surface, and wherein each said first
and second contact pads is soldered to a corresponding contact pad
of said plurality of extended purpose contact pads; and an external
housing mounted over the first surface of the PCB, wherein said
standard USB contact pads and said plurality of forward-facing pins
are disposed outside of said housing and form said connector plug
arranged such that each of said standard USB contact pads is
contacted by a corresponding standard USB contact of said extended
multiple pin USB socket and each of said first extended-purpose
contact structures is contacted by a corresponding dual-personality
contact of said extended multiple pin USB socket when said
connector plug is inserted into said extended multiple pin USB
socket, and wherein said external housing includes a socket for
removably receiving a flash memory device such that each contact
pad of the flash memory device contacts a corresponding one of said
plurality of rear-facing pins, thereby enabling communication
between said flash memory device and said dual-personality
communication IC.
16. A method for producing an USB card reader comprising: producing
a PCBA, a molded lead-frame connector, and an external housing,
wherein the PCBA includes: a printed circuit board (PCB) having
opposing first and second surfaces, a plurality of metal contacts
disposed on the first surface of the PCB, the plurality of metal
contacts including four standard USB contact pads and a plurality
of extended purpose contact pads, a dual-personality communication
integrated circuit (IC) mounted on the second surface, and a
plurality of conductive traces formed on the PCB such that each
conductive trace is electrically connected between at least one of
said plurality of metal contacts and said a dual-personality
communication IC; and wherein the molded lead-frame connector
includes a plastic molded body having a front edge, an opposing
rear edge, and a bottom surface extending between the front and
rear edges, a plurality of forward-facing pins extending from the
front edge of the plastic molded body, and a plurality of
rear-facing pins extending from the rear edge of the plastic molded
body, wherein each forward-facing pin includes an associated first
contact pad disposed on said bottom surface, wherein each
rear-facing pin includes an associated second contact pad disposed
on said bottom surface, mounting the molded lead-frame connector on
the PCBA to form a sub-assembly such that each said first and
second contact pads is soldered to a corresponding contact pad of
said plurality of extended purpose contact pads; and mounting the
sub-assembly in the external housing.
Description
FIELD OF THE INVENTION
This invention relates to portable electronic devices, and more
particularly to portable electronic devices with expanded
Universal-Serial-Bus (USB) connections.
BACKGROUND OF THE INVENTION
Universal-Serial-Bus (USB) has been widely deployed as a standard
bus for connecting peripherals such as digital cameras and music
players to personal computers (PCs) and other devices. Currently,
the top transfer rate of USB is 480 Mb/s, which is quite sufficient
for most applications. Faster serial-bus interfaces are being
introduced to address different requirements. PCI Express, at 2.5
Gb/s, and SATA, at 1.5 Gb/s and 3.0 Gb/s, are two examples of
high-speed serial bus interfaces for the next generation devices,
as are IEEE 1394 and Serial Attached Small-Computer System
Interface (SCSI).
FIG. 32(A) shows a prior-art peripheral-side USB connector. USB
connector 10 may be mounted on a board in the peripheral. USB
connector 10 can be mounted in an opening in a plastic case (not
shown) for the peripheral.
USB connector 10 contains a small connector substrate 14, which is
often white ceramic, black rigid plastic, or another sturdy
substrate. Connector substrate 14 has four or more metal contacts
16 formed thereon. Metal contacts 16 carry the USB signals
generated or received by a controller chip in the peripheral. USB
signals include power, ground, and serial differential data D+,
D-.
USB connector 10 contains a metal case that wraps around connector
substrate 14. The metal case touches connector substrate 14 on
three of the sides of connector substrate 14. The top side of
connector substrate 14, holding metal contacts 16, has a large gap
to the top of the metal case. On the top and bottom of this metal
wrap are formed holes 12. USB connector 10 is a male connector,
such as a type-A USB connector.
FIG. 32(B) shows a female USB connector. Female USB connector 20
can be an integral part of a host or PC, or can be connected by a
cable. Another connector substrate 22 contains four metal contacts
24 that make electrical contact with the four metal contacts 16 of
the male USB connector 10 of FIG. 32(A). Connector substrate 22 is
wrapped by a metal case, but small gaps are between the metal case
and connector substrate 22 on the lower three sides.
Locking is provided by metal springs 18 in the top and bottom of
the metal case. When male USB connector 10 of FIG. 32(A) is flipped
over and inserted into Female USB connector 20 of FIG. 32(B), metal
springs 18 lock into holes 12 of male USB connector 10. This allows
the metal casings to be connected together and grounded.
Flash-memory cards are widely used for storing digital pictures
captured by digital cameras. One useful format is Sony's Memory
Stick (MS), having a small form factor roughly the size of a stick
of chewing gum. Another highly popular format is Secure-Digital
(SD), which is an extension of the earlier MultiMediaCard (MMC)
format. SD cards are relatively thin, having an area roughly the
size of a large postage stamp. In addition, SD cards come in a
variety of "flavors" including micro-SD cards, which have only
eight pins.
SD cards are also useful as add-on memory cards for other devices,
such as portable music players, personal digital assistants (PDAs),
and even notebook computers. SD cards are hot-swappable, allowing
the user to easily insert and remove SD cards without rebooting or
cycling power. Since the SD cards are small, durable, and
removable, data files can easily be transported among electronic
devices by being copied to an SD card. SD cards are not limited to
flash-memory cards. Other applications such as communications
transceivers can be implemented as SD cards.
The SD interface currently supports a top transfer rate of 100
Mb/s, which is sufficient for many applications. However, some
applications such as storage and transport of full-motion video may
benefit from higher transfer rates.
Other bus interfaces offer higher transfer rates.
Universal-Serial-Bus (USB), for example, has a top transfer rate of
480 Mb/s. Peripheral-Component-Interconnect (PCI) Express, at 2.5
Gb/s, and Serial-Advanced-Technology-Attachment (SATA), at 1.5 Gb/s
and 3.0 Gb/s, are two examples of high-speed serial bus interfaces
for next generation devices. IEEE 1394 (Firewire) supports 3.2
Gb/s. Serial Attached Small-Computer System Interface (SCSI)
supports 1.5 Gb/s. These are roughly 5 to 32 times faster than the
SD interface.
What is needed is a flexible system that supports both standard
Universal-Serial-Bus (USB) devices and one or more secondary flash
memory devices (e.g., micro-Secure Digital (micro-SD) cards) using
a single (e.g., either standard USB or special dual-personality)
socket. In particular, what is needed is that serves as an
interface between a host system and the secondary flash memory
devices (e.g., a micro-SD card) by way of the special
dual-personality socket.
SUMMARY OF THE INVENTION
The present invention is directed to a dual-personality memory
system that supports both standard Universal-Serial-Bus (USB)
devices and one or more secondary flash memory devices (e.g.,
micro-Secure Digital (micro-SD) cards). A host side of the
dual-personality memory system includes a multiple pin (e.g.,
9-pin) USB female socket that is similar to a female USB socket,
but in addition to the standard (four) USB contact pins, the
extended multiple pin USB socket includes one or more additional
rows of contacts that facilitate multiple pin communications
between the host system and the secondary flash memory devices
(e.g., a micro-SD card) by way of a novel extended USB
dual-personality card reader.
The present invention is particularly directed to the extended USB
dual-personality card reader that serves as an interface between
host system (i.e., by way of the multiple pin USB female socket)
and the secondary flash memory devices (e.g., a micro-SD card). The
card reader includes at least one dual-personality communication
integrated circuit (IC), four standard USB contact pads disposed
near a front edge, several (e.g., five) front extended-purpose
contact structures positioned behind the standard USB contact pads,
several (e.g., eight) rear extended-purpose contact structures
located behind the front contact structures, and an external
housing. A front portion of the core component forms an extended,
multiple pin (e.g., 9-pin) USB (male) connector plug that includes
the standard USB contact pads and the front extended-purpose
contact structures. The external housing includes a socket (e.g., a
slot) for mounting the selected secondary flash memory devices
(e.g., a micro-SD card) such that contact structures of the
selected secondary flash memory device engage the rear
extended-purpose contact structures. The dual-personality
communication IC is configured to selectively communicate either
with a standard USB host system by way of the standard USB contact
pads (only), or with a dual-personality flash memory card system by
way of all (e.g., nine) pins of the extended, multiple pin USB male
connector plug. In addition, the dual-personality communication IC
facilitates communications between the selected secondary flash
memory device and the host system by way of the socket and
rear-facing pins. Thus, the present invention facilitates adapting
secondary memory devices (e.g., micro-SD cards) using a
dual-personality USB high speed communication protocol, and is also
backward compatible for use with a standard (e.g., USB 2.0)
communication protocol.
In accordance with an embodiment of the present invention, the
extended USB dual-personality card reader is manufactured by
separately producing a modular core component and a molded
lead-frame connector, mounting the molded lead-frame connector on
the modular core component to form a sub-assembly, and then
mounting the sub-assembly into a pre-molded external plastic
housing. The modular core component includes a PCBA in the form of
a rectangular block having all electronic components mounted to a
lower surface of a PCB and encased by a plastic molded casing such
that the upper surface of the PCB is exposed. Several metal
contacts, including the four standard USB metal contact pads and
two rows of extended-purpose contacts, are formed on the exposed
upper surface of the PCB. The molded lead-frame connector includes
several forward-facing pins extending from a front end of a plastic
molded body and have corresponding first contact pads exposed
through a lower surface of the molded body, and several rear-facing
pins extending from a rear end of the molded body that have
corresponding second contact pads exposed through the lower surface
of the molded body. The molded lead-frame connector is then mounted
onto the upper surface of the PCB such that each of the first and
second contact pads is soldered to a corresponding extended-purpose
contact pad disposed on the upper surface of the PCB. By forming
the molded lead-frame connector in this manner, assembly (mounting)
onto the PCBA of the modular core component is greatly simplified
by enabling the use of established and highly cost effective
surface-mount technology (SMT) techniques. The resulting structure
forms a connector plug with the standard USB metal contact pads and
the forward-facing pins being arranged such that, when said
connector plug is inserted into said extended multiple pin USB
socket, each of the standard USB contact pads contacts a
corresponding standard USB contact of the extended multiple pin USB
socket, and each of the forward-facing pins (extended-purpose
contact structures) contacts a corresponding dual-personality
contact of the extended multiple pin USB socket. By forming the
sub-assembly in this manner, final assembly of the card reader into
any of several external housings is greatly simplified, which
reduces manufacturing costs by simplifying the assembly
process.
According to an aspect of the invention, passive components are
mounted onto the PCB using one or more standard surface mount
technology (SMT) techniques, and one or more IC die (e.g., the
dual-personality communication IC die and a flash memory die) are
mounted using chip-on-board (COB) techniques. During the SMT
process, the SMT-packaged passive components (e.g., capacitors,
oscillators, and light emitting diodes) are mounted onto contact
pads disposed on the PCB, and then known solder reflow techniques
are utilized to connect leads of the passive components to the
contact pads. During the subsequent COB process, the IC dies are
secured onto the PCB using know die-bonding techniques, and then
electrically connected to corresponding contact pads using, e.g.,
known wire bonding techniques. After the COB process is completed,
the housing is formed over the passive components and IC dies using
plastic molding techniques. By combining SMT and COB manufacturing
techniques to produce modular USB core components, the present
invention provides several advantages over conventional
manufacturing methods that utilize SMT techniques only. First, by
utilizing COB techniques to mount the USB controller and flash
memory, the large PCB area typically taken up by SMT-packaged
controllers and flash devices is dramatically reduced, thereby
facilitating significant miniaturization of the resulting USB
device footprint (i.e., providing a shorter device length and
thinner device width). Second, the IC die height is greatly
reduced, thereby facilitating stacked memory arrangements that
greatly increase memory capacity of the USB devices without
increasing the USB device footprint. Further, overall manufacturing
costs are reduced by utilizing unpackaged controllers and flash
devices (i.e., by eliminating the cost associated with SMT-package
normally provided on the controllers and flash devices). Moreover,
the molded housing provides greater moisture and water resistance
and higher impact force resistance than that achieved using
conventional manufacturing methods. Therefore, the combined COB and
SMT method according to the present invention provides a less
expensive and higher quality (i.e., more reliable) memory product
with a smaller size than that possible using conventional SMT-only
manufacturing methods.
According to an aspect of the present invention, the sub-assembly
formed by mounting the molded lead-frame connector on the modular
USB core component in the manner described above is disposed in a
variety of plastic molded external housings so as to form a variety
of card readers, each having a slot for receiving a micro-SD card.
By forming the sub-assembly including the PCBA and the molded
lead-frame connector, and then mounting the sub-assembly into an
external housing, the present invention greatly simplifies the
assembly process, thus reducing overall costs.
According to an aspect of the present invention, the sub-assembly
formed by mounting the molded lead-frame connector on the modular
USB core component in the manner described above is disposed in a
variety of plastic molded external housings so as to form a variety
of card readers, each having a slot for receiving a micro-SD card.
By forming the sub-assembly including the PCBA and the molded
lead-frame connector, and then mounting the sub-assembly into an
external housing, the present invention greatly simplifies the
assembly process, thus reducing overall costs.
In addition to providing functions as a micro-SD card reader, in
accordance with another embodiment card readers include
dual-purpose controllers that are modified to serve both as
"standard" USB devices and as micro-SD card readers, thus enhancing
their functionality. In alternative embodiments, significant memory
capacity for use in the USB device mode (i.e., without requiring
the insertion of a micro-SD card) are provided without increasing
the overall size of card reader 101-1 by stacking flash memory die,
and by combining the dual-purpose controller and flash memory in a
single IC.
BRIEF DESCRIPTION OF THE DRAWINGS
These and other features, aspects and advantages of the present
invention will become better understood with regard to the
following description, appended claims, and accompanying drawings,
where:
FIGS. 1(A) and 1(B) are perspective top and cross sectional side
views showing a dual-personality USB memory system including an
extended USB dual-personality card reader according to a simplified
embodiment of the present invention;
FIG. 2 is a simplified block diagram showing a host system of the
dual-personality USB memory system of FIG. 1;
FIGS. 3(A) and 3(B) are exploded perspective and assembled
perspective views showing a sub-assembly of the extended USB
dual-personality card reader of FIG. 1 according to a specific
embodiment of the present invention;
FIGS. 4(A) and 4(B) are an enlarged cross-sectional view showing a
molded lead-frame connector of the sub-assembly of FIGS. 3(A) and
3(B), and a simplified cross-sectional view of the sub-assembly of
FIG. 3(B), respectively;
FIG. 5 is a flow diagram depicting a method for producing the
extended USB dual-personality card reader of FIG. 2 according to
another embodiment of the present invention;
FIGS. 6(A) and 6(B) are top perspective and partial bottom
perspective views showing a PCB panel utilized in the method of
FIG. 5;
FIGS. 7(A) and 7(B) are bottom perspective views showing a PCB of
the PCB panel of FIG. 6(A) during and after the SMT process;
FIGS. 8(A), 8(B), 8(C) and 8(D) are simplified perspective and
cross-sectional side views depicting a semiconductor wafer and a
process of grinding and dicing the wafer to produce IC dies
utilized in the method of FIG. 5;
FIGS. 9(A) and 9(B) are perspective views depicting a die bonding
process utilized to mount the IC dies of FIG. 8(D) on a PCB
according to the method of FIG. 5;
FIGS. 10(A) and 10(B) are perspective views depicting a wire
bonding process utilized to connect the IC dies to corresponding
contact pads disposed on the PCB of FIG. 9(B) according to the
method of FIG. 5;
FIGS. 11(A) and 11(B) are simplified cross-sectional side views
depicting a molding process for forming a molded housings over the
PCB panel according to the method of FIG. 5;
FIG. 12 is a top perspective views showing the PCB panel after the
molding process is completed;
FIGS. 13(A) and 13(B) are perspective views showing a lead frame
panel and a lead frame of the panel, respectively, that are used to
produce molded lead-frame connectors according to the method of
FIG. 5;
FIGS. 14(A) and 14(B) are perspective views showing the lead frame
panel and the lead frame of FIGS. 15(A) and 15(B), respectively,
after a molded body is formed on ends of the leads;
FIGS. 15(A) and 15(B) an exploded perspective view showing a PCB
and a PCB panel, respectively, depicting an SMT process utilized to
mount the lead-frame connectors of FIG. 14(B) on PCBs according to
the method of FIG. 5;
FIG. 16 is a cross-sectional side view showing a singulation
process according to the method of FIG. 5;
FIG. 17 is an exploded perspective view showing a card reader
according to an embodiment of the present invention;
FIGS. 18(A) and 18(B) are exploded perspective and front top
perspective views, respectively, showing assembly of a sub-assembly
into a housing portion of FIG. 17 according to an embodiment of the
present invention;
FIGS. 19(A) and 19(B) are exploded perspective and front top
perspective views, respectively, showing assembly of a plug shell
onto the partial assembly of FIG. 18(B) according to an embodiment
of the present invention;
FIGS. 20(A), 20(B) and 20(C) are exploded perspective, front top
perspective and front bottom perspective views, respectively,
showing a final assembly step for completing a card reader
according to an embodiment of the present invention;
FIG. 21 is an exploded perspective view showing the insertion of a
micro-SD card into the card reader of FIG. 20(B);
FIGS. 22(A) and 22(B) are cross-sectional side views showing the
insertion of a micro-SD card into the card reader of FIG.
20(B);
FIG. 23 is a block diagram showing a dual-personality controller
circuit of a card reader according to an embodiment of the present
invention;
FIG. 24 is simplified cross-sectional side view showing a modular
USB device including stacked-memory according to another embodiment
of the present invention;
FIG. 25 is simplified cross-sectional side view showing a
single-chip modular USB device according to another embodiment of
the present invention;
FIG. 26 is an exploded perspective view showing a card reader
according to another embodiment of the present invention;
FIGS. 27(A) and 27(B) are bottom rear and top front perspective
views showing the card reader of FIG. 26 after assembly is
completed;
FIG. 28 is an exploded perspective view showing a card reader
according to another embodiment of the present invention;
FIGS. 29(A) and 29(B) are rear and front perspective views showing
the card reader of FIG. 28 after assembly is completed;
FIG. 30 is an exploded perspective view showing a card reader
according to another embodiment of the present invention;
FIGS. 31(A) and 31(B) are rear and front perspective views showing
the card reader of FIG. 30 after assembly is completed; and
FIGS. 32(A) and 32(B) are front perspective views showing a
conventional USB male plug and a conventional USB female socket,
respectively.
DETAILED DESCRIPTION OF THE DRAWINGS
The present invention relates to an improved method for
manufacturing USB devices, and in particular to USB assemblies
manufactured by the method. The following description is presented
to enable one of ordinary skill in the art to make and use the
invention as provided in the context of a particular application
and its requirements. As used herein, the terms "upper", "upwards",
"lower", and "downward" are intended to provide relative positions
for purposes of description, and are not intended to designate an
absolute frame of reference. Various modifications to the preferred
embodiment will be apparent to those with skill in the art, and the
general principles defined herein may be applied to other
embodiments. Therefore, the present invention is not intended to be
limited to the particular embodiments shown and described, but is
to be accorded the widest scope consistent with the principles and
novel features herein disclosed.
FIGS. 1(A) and 1(B) showing a dual-personality USB memory system
100 including an extended 9-pin (multiple pin) USB female socket
190 that communicates with both standard USB devices and
micro-Secure-Digital (micro-SD) cards 50 by way of an extended USB
dual-personality card reader 101 that is manufactured and operates
in accordance with the present invention. That is, in accordance
with the exemplary embodiment, dual-personality USB memory system
100 is operated to process (receive and transmit) both standard USB
signals and micro-Secure-Digital (micro-SD) card signals through
extended 9-pin USB socket 190 in a manner consistent with that
described in co-owned U.S. Pat. No. 7,108,560, entitled "Extend USB
Protocol Plug and Receptacle for implementing Single-Mode
Communication", which is incorporated herein by reference.
Referring to the right side of FIG. 1(A) and FIG. 1(B), card reader
101 generally includes a printed circuit board assembly (PCBA),
extended-use contact structures 172 and 175 disposed on PCBA 110,
and an external housing 180. PCBA 110 includes a printed circuit
board (PCB) 111 having opposing upper (first) surface 116 and an
opposing lower (second) surface 118. Four standard USB (metal)
contact pads 121, five extended-use (metal) contact pads 122, and
eight extended-use (metal) contact pads 125 are disposed on upper
surface 116. A dual-personality communication integrated circuit
(IC) 130 is mounted on lower surface 118, and conductive traces
(not shown) are formed on PCB 111 using known techniques such that
contacts 121, 122, 125 are connected to dual-personality
communication IC 130. Five extended-use contact structures 172 are
disposed on upper surface 116 such that they are respectively
electrically connected (e.g., soldered) to corresponding
extended-use contact pads 122, and eight extended-use contact
structures 175 are also disposed on upper surface 116 and
respectively electrically connected to corresponding extended-use
contact pads 125. External housing 180 (shown in dashed lines for
illustrative purposes) is mounted over first surface 116 of PCB 111
and is arranged behind (i.e., to the right in FIG. 1(A)) of
extended-use contact structures 172, whereby standard USB contact
pads 121 and extended-purpose contact structures 172 are disposed
outside of housing 180 and form a connector plug 114. In addition,
housing 180 includes a socket (slot) 187 for removably receiving a
micro-SD card (flash memory device) 50 such that each contact pad
55 of the micro-SD card 50 contacts a corresponding one of
extended-use contact structures 175, thereby enabling communication
between micro-SD card 50 and dual-personality communication IC 130
in the manner described below. Other features and details
associated with card reader 101 are provided below.
Because many conventional USB (male) connectors and (female)
sockets (also referred to as standard USB plug connectors and
standard USB sockets herein) are widely deployed, it is
advantageous for the improved enhanced USB connector to be
compatible with standard USB sockets, and an enhanced USB socket to
be compatible with standard USB connectors for backward
compatibility. Although the height and width of USB
connectors/sockets have to remain the same for insertion
compatibility, the length of each may be extended to fit additional
metal contacts for additional signals. Furthermore, additional
metal contacts (pins) may be disposed on the plug connector, either
adjacent to opposite the existing four standard USB metal contacts.
As indicated in FIG. 1(A), plug connector 114 of card reader 101
represents such extended plug connector that includes the four
standard USB metal contact pads 121 and the five additional
(extended-use) contact structures 172 that are disposed in a row
behind standard USB metal contact pads 121.
Referring to FIG. 1(B), to support communications with card reader
101, extended 9-pin USB female socket 190 includes four standard
USB metal contact pins 191 and five additional (dual-personality)
contact pads 192 that are disposed on the bottom surface of a pin
substrate 194 to engage standard USB metal contact pads 121 and
additional contact structures 172 when plug connector 114 is
inserted therein. Female socket 190 also includes an outer (e.g.,
metal) casing 196 that cooperates with substrate 194 to define a
cavity (slot) 197 for receiving plug connector 114. FIG. 1(B) shows
plug connector 114 inserted into 9-pin USB socket 190 such that
standard USB metal contact pins 191 of socket 190 contact standard
USB metal contacts 121 of card reader 101, and additional contact
pads 192 of socket 190 contact additional contact structures 172 of
card reader 101, thereby facilitating 9-pin communication between
card reader 101 and a host system controller (not shown) that is
connected to socket 190.
FIG. 2 is a block diagram of an exemplary host 105 with one
embodiment of extended-USB socket 190 that supports extended-mode
communication. Although the description below refers only to
communications with standard USB devices 60 and micro-SD cards 55
via card reader 101, those skilled in the art will recognize that
the sockets and card reader features described herein can be
altered to accommodate one or more of a variety of other flash
memory devices (e.g., SD, MMC, SATA, PCI-Express, Firewire IEEE
1394, or Serial-Attached SCSI). As shown in FIG. 2, host system 105
includes a processor 106 for executing programs including
USB-management and bus-scheduling programs. Dual-personality
serial-bus interface 107 processes data from processor 106 using
two protocol processors including a standard USB protocol processor
109A and a micro-SD protocol processor 109B. USB processor 109A
processes data using the USB protocol, and inputs and outputs USB
data on the four standard USB contacts 191 in extended USB socket
190. The extended metal contact pins in extended USB socket 190
connect to dual-personality bus switch 107. Transceivers in
dual-personality bus switch 107 buffer data to and from the
transmit and receive pairs of differential data lines in the
extended metal contacts for the "extended" micro-SD protocol. When
an initialization routine executed by processor 106 determines that
inserted flash memory device supports the micro-SD protocol,
personality selector 108 configures dual-personality bus switch 107
to connect extended USB socket 190 to micro-SD processor 109B.
Processor 106 communicates with micro-SD processor 109B instead of
USB processor 109A when extended mode is activated. Additional
details regarding the operation of host 105 will be apparent to
those skilled in the art based on the teachings in U.S. Pat. No.
7,108,560 (cited above) and the description provided below.
FIGS. 3(A) and 3(B) are perspective and cross-sectional side views
showing an exemplary card reader subassembly 101A including a
modular USB core component 102 and a molded lead-frame connector
170. As set forth below, and with reference to the flow diagram of
FIG. 4, extended USB dual-personality card readers produced in
accordance with the present invention include sub-assembly 101A is
manufactured by separately producing a modular core component 102
and molded lead-frame connector 170, mounting molded lead-frame
connector 170 on the modular core component 102 to form
sub-assembly 101A, and then mounting the sub-assembly 101A into a
pre-molded external plastic housing (not shown in FIGS. 2(A) and
2(B); discussed below). By forming sub-assembly 101A in this
manner, final assembly of card readers produced in accordance with
the present invention using any of several external housings is
greatly simplified, which reduces manufacturing costs by
simplifying the assembly process.
Referring to the lower portion of FIG. 3(A), modular core component
102 generally includes a printed circuit board assembly (PCBA) 110
and a plastic housing 150 that is molded onto PCBA 110. PCBA 110
includes a printed circuit board (PCB) 111, metal contact pads 120,
IC dies 130 and passive components 140. PCB 111 is a substantially
flat substrate, and has opposing sides that are referred to below
as upper (first) surface 116 and lower (second) surface 118. Metal
contacts 120 are formed on upper surface 116, and include four
standard USB metal contact pads 121 that are shaped and arranged in
a pattern established by the USB specification, and two rows of
extended-purpose contacts including five (first) contacts 121 and
eight (second) contacts 125. IC dies 130 include (but are not
limited to) a dual-personality communication IC 131, a central
processing unit IC 135 and flash memory IC 137, and are
electrically connected to contact pads 119 formed on lower surface
118 in the manner described below. Passive components 140 include
(but are not limited to) resistor and/or capacitor components 142
and an oscillator 144, and are also connected to contact pads 119
formed on lower surface 118 in the manner described below. PCB 111
is formed in accordance with known PCB manufacturing techniques
such that metal contacts 120, IC dies 130, and passive components
10 are electrically interconnected by a predefined network
including conductive traces 129 and other conducting structures
that are sandwiched between multiple layers of an insulating
material (e.g., FR4) and adhesive.
Housing 150 is molded plastic formed and arranged such that
substantially all of the plastic used to form housing 150 is
located below (i.e., on one side of) PCB 111. As indicated in FIG.
3(B), housing 150 includes a peripheral surface 151 extending
downward (i.e., perpendicular to PCB 111), and a lower surface 152
that extends parallel to PCB 111. For discussion purposes, the
portion of peripheral surface 151 surrounding handle section 112 of
PCB 111 is referred to below as handle surface section 151-1, and
the section of peripheral surface 151 surrounding plug section 114
of PCB 111 is referred to below as plug surface section 151-2.
Similarly, the portion of lower surface 152 covering handle section
112 of PCB 111 is referred to below as handle surface section
152-1, and the section of lower surface 152 covering plug section
114 of PCB 111 is referred to below as plug cover section
152-2.
Referring again to FIGS. 3(A) and 3(B), in accordance with another
aspect of the present embodiment, molded lead-frame connector 170
of sub-assembly 101A includes five forward-facing pins 172
extending from a front edge (end) 171F of a plastic molded body 171
and have corresponding first contact pads 172A exposed through a
lower surface 171B of molded body 171, and eight rear-facing pins
175 extending from a rear edge 171R of molded body 171 and have
corresponding second contact pads 175A exposed through lower
surface 171B. As set forth in detail below, molded lead-frame
connector 170 is manufactured by forming molded plastic body 171
over contact pads 172A and 175A, and then trimming the outer ends
of forward-facing pins 172 and rear-facing pins 175 from a
supporting a lead-frame (not shown). As indicated in FIGS. 3(A) and
3(B), molded lead-frame connector 170 is then mounted onto upper
surface 116 of PCB 111 such that each of the contact pads 172A and
175A is electrically connected (e.g., soldered) to a corresponding
extended-purpose contact pad 122 or 125. By forming the molded
lead-frame connector in this manner, assembly (mounting) onto the
PCBA of the modular core component is greatly simplified by
enabling the use of established and highly cost effective
surface-mount technology (SMT) techniques.
FIG. 4(A) is an enlarged cross-sectional view showing a molded
lead-frame connector 170 in additional detail, and FIG. 4(B) is a
cross-sectional view showing assembly 101A.
Referring to FIG. 4(A), in accordance with another aspect of the
present invention, each forward-facing pin 172 of molded lead-frame
connector 170 further includes a step portion 172S extending from
its contact pad 172A into plastic molded body 171. Similarly, each
rear-facing pin 175 includes a step portion 175S extending from its
contact pad 175 into plastic molded body 171. Step portions 172S
and 175S serve to anchor forward-facing pins 172 and rear-facing
pins 175 to molded body 171, thereby providing an especially strong
lead-to-plastic bond that resists damage due to bending forces
applied to forward-facing pins 172 and rear-facing pins 175.
As also shown in FIG. 4(A), in accordance with another aspect of
the present invention, each forward-facing pin 172 of molded
lead-frame connector 170 further includes a curved (bent) spring
section 172C extending upward from the otherwise straight-line lead
structure, and similarly, each rear-facing pin 175 includes a
curved spring 175C. Curved spring sections 172C and 175C serve to
facilitate good electrical contact between forward-facing pins 172
and socket 190 (see FIG. 1), and between rear-facing pins 175 and
micro-SD card 50 (see FIG. 1). In particular, curved spring
sections 175C are provided for contacting a micro-SD connector
pin's pads. When the micro-SD device's pad is slid over a
corresponding curved spring section 175C of a particular pin 175,
the lead tip of the pad slides along the associated pin 175 and
pushes the associated curved spring section 175C downward, thus
decreasing its height due to the compressive force caused by the
thickness of the micro-SD card, which is thicker than the gap
between curved spring section 175C and the upper package ceiling.
Thus, this slightly depressed curved spring section 175C provides
an upward thrusting force that enables the micro-SD pads make good
electrical contact with connector pins 175. Similarly, curved
spring sections 172C of forward-facing pins 172 are provided to
make good electrical contact between card reader 101 and
corresponding contact pads of socket 190 (see FIG. 1).
In accordance with another aspect of the present invention, the
structure (i.e., sub-assembly 101A) resulting from mounting molded
lead-frame connector 170 onto modular core component 102 provides a
connector plug 114 that includes the section of modular core
component 102 that includes standard USB metal contact pads 121,
and that extends in front of forward-facing pins 172. Note that, by
forming modular core component 102 and molded lead-frame connector
170 in the manner described above, standard USB metal contact pads
121 and forward-facing pins 172 are arranged such that, when said
connector plug 114 is inserted into extended multiple pin USB
socket 190 (see FIG. 1(A)), each standard USB contact pad 121
contacts a corresponding standard USB contact 191 of socket 190,
and each forward-facing pin 172 contacts a corresponding
dual-personality contact 192 of socket 190. As set forth below, by
forming sub-assembly 101A in this manner, final assembly of the
card reader into any of several external housings is greatly
simplified, which reduces manufacturing costs by simplifying the
assembly process.
Referring to FIG. 4(B), according to another aspect of the
invention, passive components 140 are mounted onto lower surface
118 using one or more standard surface mount technology (SMT)
techniques, and one or more IC dies 130 are mounted using
chip-on-board (COB) techniques. As indicated in FIG. 4(B), during
the SMT process, the passive components, such as
resistors/capacitors 142 and oscillator 144 are mounted onto
associated contact pads 119 (described below) disposed on lower
surface 118, and are then secured to the contact pads using known
solder reflow techniques. To facilitate the SMT process, each of
the passive components is packaged in any of the multiple known
(preferably lead-free) SMT packages (e.g., ball grid array (BGA) or
thin small outline package (TSOP)). In contrast, IC dies 130 are
unpackaged, semiconductor "chips" that are mounted onto surface 118
and electrically connected to corresponding contact pads using
known COB techniques. For example, as indicated in FIG. 4(B), dual
IC die 130 is electrically connected to PCB 111 by way of wire
bonds 160-1 that are formed using known techniques. Similarly,
flash memory IC die 135 is electrically connected to PCB 111 by way
of wire bonds 160-2. Passive components 142 and 144, IC dies 131
and 135 and metal contacts 120 are operably interconnected by way
of metal traces 129 that are formed on and in PCB 111 using known
techniques, a few of which being depicted in FIG. 3(A) in a
simplified manner by short dashed lines.
Referring to FIGS. 3(B) and 4(B), a thickness T1 and width W1 of
connector plug 114 is selected to produce a secure (snug) fit
inside either an external case (discussed below) or directly into
socket 190 (see FIG. 1).
As indicated in FIG. 4(B), according to another aspect of the
present invention, housing 150 includes a planar surface 152 that
is parallel to PCB 111, and defines a single plane such that a
first thickness T1 of connector plug 114 (i.e., measured between
upper PCB surface 116 and planar surface 152 adjacent to metal
contacts 121) is substantially equal to a second thickness T2
adjacent a rear end of (i.e., measured between upper PCB surface
116 and planar surface 152 adjacent to passive component 142. That
is, as indicated in FIG. 2(B), modular USB core component 102 is
substantially flat along its entire length (i.e., from rear edge
151-1A to front edge 151-1B). The term "substantially flat" is
meant to indicate that planar surface 152 is substantially parallel
to an uppermost surface of modular USB core component 102 along its
entire length. In the embodiment shown in FIG. 4(B), the uppermost
surface of modular USB core component 102 is defined in part by
upper surface 116 of PCB 111, which is parallel to planar surface
152 along the entire length of USB core component 102. Similarly,
the term "substantially flat" is also intended to cover embodiments
described below in which the housing includes a thin wall structure
that is formed on or otherwise contacts the upper surface of the
PCB. In these embodiments, the thickness T2 of handle structure 102
may differ by a small amount (e.g., 5% from thickness T1 of plug
structure 105.
According to an aspect of the present invention, the "flatness"
associated with modular USB core component 102 is achieved by
mounting all of the IC dies ("chips") and other electronic
components of modular USB core component 102 on lower surface 118
of PCB 111 (i.e., on the side opposite to metal contacts 121). That
is, the minimum overall thickness of modular USB core component 102
is determined by the thickness T1 that is required to maintain a
snug connection between connector plug 114 and female USB socket
connector 190 (see FIG. 1). Because this arrangement requires that
metal contacts 121 be located at the uppermost surface, and that
plug wall section 151-2 plug and cover section 152-2 extend a
predetermined distance below PCB 111 to provide the required
thickness T1. Thus, the overall thickness of modular USB core
component 102 can be minimized by mounting the IC dies 130 and 135
and passive components (e.g., capacitor 142) only on lower surface
118 of PCB 111. That is, if the IC dies and passive components are
mounted on upper surface 116, then the overall thickness of the
resulting USB structure would be the required thickness T1 plus the
thickness that the ICs extend above PCB 111 (plus the thickness of
a protective wall, if used).
According to another aspect associated with the embodiment shown in
FIGS. 3(B) and 4(B), upper surface 116 of PCB 111 is entirely
exposed on the upper surface of modular USB core component 102,
thus facilitating the production of USB core component 102 with a
maximum thickness equal to thickness T1 of plug structure 105, and
also facilitating the production of sub-assembly 101A. That is,
because metal contacts 120 are formed on upper surface 116, and
upper surface 116 defines the higher end of required plug structure
thickness T1, the overall height of modular USB core component 102
can be minimized by exposing upper surface 116 (i.e., by making any
point on upper PCB surface 116 the uppermost point of modular USB
core component 102). In addition, by exposing the entirety of upper
surface 116, this arrangement facilitates the use of SMT techniques
in the mounting of molded lead-frame connector 170 onto PCBA 110 to
form sub-assembly 101A. As indicated in FIG. 4(B), in accordance
with feature specifically associated with modular USB core
component 102, peripheral wall 151 extends around up to but does
not cover the peripheral side edges of PCB 111 (e.g., front edge
151-1B and rear edge 151-1A extend up to PCB 111, but edges 111P-2
and 111P-1 remain exposed). In an alternative embodiment (not
shown), an upper edge of peripheral wall 151 may extend over the
peripheral edge of PCB 111 to help prevent undesirable separation
of PCBA 110 from housing 150.
FIG. 5 is a flow diagram showing a method for producing an extended
USB dual-personality card reader according to another embodiment of
the present invention. Summarizing the novel method, a panel of
modular core components is fabricated (blocks 210 to 250) and
individual molded lead-frame connectors are produced (blocks
260-268), the molded lead-frame connectors are then mounted onto
the panel of modular core components (block 270) which is then
singulated into individual sub-assemblies (block 275), which in
turn are then mounted into external housings that are tested and
shipped (blocks 280-295).
Referring to the upper portion of FIG. 5, the fabrication of a
modular core component panel begins with generating a PCB panel
using known techniques (block 210) and passive components are
procured (block 212, and then passive components are mounted on the
PCB panel using SMT techniques (block 220). In parallel, IC dies
are produced by fabricating/procuring processed wafers (block 230),
performing wafer back grind (block 232) and wafer dicing (block
234), and then the resulting IC dies are die bonded (block 240) and
wire bonded (block 245) using known COB techniques onto
corresponding sections of the PCB panel. Molten plastic is then
used to form a molded housing over the passive components and the
IC dies (block 250), thus completing the modular core component
panel. This method provides several advantages over conventional
manufacturing methods that utilize SMT techniques only. First, by
utilizing COB techniques to mount the USB controller and flash
memory, the large amount of space typically taken up by these
devices is dramatically reduced, thereby facilitating significant
miniaturization of the resulting USB device footprint. Second, by
implementing the wafer grinding methods described below, the die
height is greatly reduced, thereby facilitating stacked memory
arrangements such as those described below. The molded housing also
provides greater moisture and water resistance and higher impact
force resistance than that achieved using conventional
manufacturing methods. In comparison to the standard USB memory
card manufacturing that used SMT process, it is cheaper to use the
combined COB and SMT (plus molding) processes described herein
because, in the SMT-only manufacturing process, the bill of
materials such as Flash memory and the Controller chip are also
manufactured by COB process, so all the COB costs are already
factored into the packaged memory chip and controller chip.
Therefore, the combined COB and SMT method according to the present
invention provides a less expensive and higher quality (i.e., more
reliable) card reader product with a smaller size than that
possible using conventional SMT-only manufacturing methods.
Referring to the right side of FIG. 5, the molded lead-frame
connectors are separately fabricated form mounting onto the core
component panel. A lead-frame is produced by providing a suitable
metal sheet strip (block 260), cutting and down setting the strip
to form a lead frame (block 262), and then performing
electroplating on the lead frame (block 264) according to known
lead frame manufacturing techniques. The lead-frame is then
inserted into a plastic molding machine and molded plastic bodies
are formed on the lead frame (block 266). The lead frame is then
cut (singulated) to provide the individual molded lead-frame
connectors (block 268). Next, the molded lead-frame connectors are
mounted onto the modular core component panel using SMT techniques
(block 270), and the panel is then subjected to singulation
(cutting) to separate the panel into individual sub-assemblies,
each sub-assembly having the structure described above with
reference to FIGS. 3(A), 3(B) and 4(B). This process produces
sub-assemblies having high accuracy and strength, thus greatly
facilitating the low-cost production of extended USB
dual-personality card readers according to the present
invention.
Final assembly is then performed by producing/procuring external
housings (e.g., as indicated by simplified housing 180 in FIG. 1
and described in additional detail below; block 280), and each
sub-assembly is mounted into an associated external housing (block
290), thereby providing completed extended USB dual-personality
card readers. Each extended USB dual-personality card reader is
tested, packed and shipped (block 295) according to customary
practices.
The flow diagram of FIG. 5 will now be described in additional
detail below with reference to the following figures.
Referring to the upper portion of FIG. 5, the manufacturing method
begins with filling a bill of materials including
producing/procuring PCB panels (block 210), producing/procuring
passive (discrete) components (block 212) such as resistors,
capacitors, diodes, LEDs and oscillators that are packaged for SMT
processing, and producing/procuring a supply of IC wafers (or
individual IC dies).
FIG. 6(A) is a top perspective view showing a PCB panel 300(t0)
provided in block 210 of FIG. 3 according to a specific embodiment
of the present invention. FIG. 6(B) is a bottom perspective view
showing one PCB 111 of PCB panel 300(t0). The suffix "tx" is
utilized herein to designated the state of the PCB panel during the
manufacturing process, with "t0" designating an initial state.
Sequentially higher numbered prefixes (e.g., "t1", "t2" and "t3")
indicate that PCB panel 300 has undergone additional
processing.
As indicated in FIG. 6(A), PCB panel 300(t0) includes a two-by-nine
matrix of regions designated as PCBs 111, each having the features
described above with reference to FIG. 3(A). FIG. 6(A) shows upper
surface 116 of each PCB 111 (e.g., upper surface 116 of panel 111-1
includes metal contacts 121, 122 and 125, described above), and
FIG. 6(B) shows lower surface 118 of PCB 111-1. Note that lower
surface 118 of each PCB 111 (e.g., PCB 111-1) includes multiple
contact pads 119 arranged in predetermined patterns for
facilitating SMT and COB processes, as described below.
As indicated in FIG. 6(A), in addition to the two rows of PCBs 111,
panel 300(t0) includes end border regions 310 and side border
regions 320 that surround the PCBs 111, and a central region 340
disposed between the two rows of PCBs 111. Designated cut lines are
scored or otherwise partially cut into PCB panel 300(t0) along the
borders of each of these regions, but do not pass through the panel
material. For example, end cut lines 311 separate end border panels
310 from associated PCBs 111, side cut lines 321 separate side
border panels 310 from associated PCBs 111, and central cut lines
341 separate central region 340 from associated PCBs 111. PCB cut
lines 331 are formed along the side edges between adjacent PCBs
111. The border panels are provided with positioning holes and
other features known to those skilled in the art to facilitate the
manufacturing process, and are removed during singulation
(described below).
Note that PCBs for USB devices that are produced using SMT-only
manufacturing processes must be significantly wider than PCBs 111
due to the space required to mount already packaged flash memory
devices. As such, PCB panels for SMT-only manufacturing methods
typically include only twelve PCBs arranged in a 2.times.6 matrix.
By utilizing COB methods to mount the flash memory, the present
invention facilitates significantly narrower PCB 111, thereby
allowing each PCB panel 300(t0) to include 18 PCBs 111 arranged in
a 2.times.9 matrix. By increasing the number of PCBs 111 per PCB
panel, the present invention provides shorter manufacturing time
and hence lower cost.
FIG. 7(A) is a perspective view depicting a portion of panel
300(t0) that is used to mount passive components on PCB 111-1
according to block 220 of FIG. 5. During the first stage of the SMT
process, lead-free solder paste is printed on contact pads 119-1
and 119-2, which in the present example correspond to SMT
components 142 and 144, using custom made stencil that is tailored
to the design and layout of PCB 111-1. After dispensing the solder
paste, the panel is conveyed to a conventional pick-and-place
machine that mounts SMT components 142 and 144 onto contact pads
119-1 and 119-2, respectively, according to known techniques. Upon
completion of the pick-and-place component mounting process, the
PCB panel is then passed through an IR-reflow oven set at the
correct temperature profile. The solder of each pad on the PC board
is fully melted during the peak temperature zone of the oven, and
this melted solder connects all pins of the passive components to
the finger pads of the PC board. FIG. 7(B) shows PCB 111-1 of the
resulting PCB panel 300(t1), which now includes passive components
142 and 144 mounted thereon by the completed SMT process.
FIG. 8(A) is a simplified perspective view showing a semiconductor
wafer 400(t0) procured or fabricated according to block 230 of FIG.
5. Wafer 400(t0) includes multiple ICs 430 that are formed in
accordance with known photolithographic fabrication (e.g., CMOS)
techniques on a semiconductor base 401. In the example described
below, wafer 400(t1) includes ICs 430 that comprise, e.g.,
dual-personality communication ICs. In a related procedure, a wafer
(not shown) similar to wafer 400(t1) is produced/procured that
includes flash memory circuits, and in an alternative embodiment
(described in additional detail below), ICs 430 may include both
dual-personality communication ICs and flash memory circuits. In
each instance, these wafers are processed as described herein with
reference to FIGS. 8(B), 8(C) and 8(D).
As indicated in FIGS. 8(B) and 8(C), during a wafer back grind
process according to block 232 of FIG. 5, base 401 is subjected to
a grinding process in order to reduce the overall initial thickness
TW1 of each IC 430. Wafer 400(t1) is first mount face down on
sticky tape (i.e., such that base layer 401(t0) faces away from the
tape), which is pre-taped on a metal or plastic ring frame (not
shown). The ring-frame/wafer assembly is then loaded onto a vacuum
chuck (not shown) having a very level, flat surface, and has
diameter larger than that of wafer 400(t0). The base layer is then
subjected to grinding until, as indicated in FIG. 8(C), wafer
400(t1) has a pre-programmed thickness TW2 that is less than
initial thickness TW1 (shown in FIG. 8(B)). The wafer is cleaned
using de-ionized (D1) water during the process, and wafer 400(t1)
is subjected to a flush clean with more D1 water at the end of
mechanical grinding process, followed by spinning at high speed to
air dry wafer 400(t1).
Next, as shown in FIG. 8(D), the wafer is diced (cut apart) along
predefined border regions separating ICs 430 in order to produce IC
dies 130 according to block 234 of FIG. 5. After the back grind
process has completed, the sticky tape at the front side of wafer
400(t1) is removed, and wafer 400(t1) is mounted onto another ring
frame having sticky tape provided thereon, this time with the
backside of the newly grinded wafer contacting the tape. The ring
framed wafers are then loaded into a die saw machine. The die saw
machine is pre-programmed with the correct die size information,
X-axis and Y-axis scribe lanes' width, wafer thickness and intended
over cut depth. A proper saw blade width is then selected based on
the widths of the XY scribe lanes. The cutting process begins
dicing the first lane of the X-axis of the wafer. De-ionized wafer
is flushing at the proper angle and pressure around the blade and
wafer contact point to wash and sweep away the silicon saw dust
while the saw is spinning and moving along the scribe lane. The
sawing process will index to the second lane according to the die
size and scribe width distance. After all the X-axis lanes have
been completed sawing, the wafer chuck with rotate 90 degree to
align the Y-axis scribe lanes to be cut. The cutting motion
repeated until all the scribe lanes on the Y-axis have been
completed.
FIG. 9(A) is a perspective view depicting a die bonding process
utilized to mount IC dies 131, 135 and 137 on PCB 111-1 of the PCB
panel 300(t1) (described above with reference to FIG. 7(B))
according to block 240 of FIG. 5. The die bonding process generally
involves mounting IC dies 131 into lower surface region 118A, which
is surrounded by contact pads 119-4, mounting IC die 135 into lower
surface region 118B, which is surrounded by contact pads 119-5, and
mounting IC die 137 into lower surface region 118C, which is
surrounded by contact pads 119-6. In one specific embodiment, an
operator loads IC dies 131, 135 and 137 onto a die bonder machine
according to known techniques. The operator also loads multiple PCB
panels 300(t1) onto the magazine rack of the die bonder machine.
The die bonder machine picks the first PCB panel 300(t1) from the
bottom stack of the magazine and transports the selected PCB panel
from the conveyor track to the die bond (DB) epoxy dispensing
target area. The magazine lowers a notch automatically to get ready
for the machine to pick up the second piece (the new bottom piece)
in the next cycle of die bond operation. At the die bond epoxy
dispensing target area, the machine automatically dispenses DB
epoxy, using pre-programmed write pattern and speed with the
correct nozzle size, onto the target areas 118A, 118B and 118C of
each of the PCB 111 of PCB panel 300(t1). When all PCBs 111 have
completed this epoxy dispensing process, the PCB panel is conveyed
to a die bond (DB) target area. Meanwhile, at the input stage, the
magazine is loading a second PCB panel to this vacant DB epoxy
dispensing target area. At the die bond target area, the pick up
arm mechanism and collet (suction head with rectangular ring at the
perimeter so that vacuum from the center can create a suction
force) picks up an IC die 131 and bonds it onto area 118A, where
epoxy has already dispensed for the bonding purpose, and this
process is then performed to place IC dies 135 and 137 into regions
118B and 118C. Once all the PCB boards 111 on the PCB panel have
completed die bonding process, the PCB panel is then conveyed to a
snap cure region, where the PCB panel passes through a chamber
having a heating element that radiates heat having a temperature
that is suitable to thermally cure the epoxy. After curing, the PCB
panel is conveyed into the empty slot of the magazine waiting at
the output rack of the die bonding machine. The magazine moves up
one slot after receiving a new panel to get ready for accepting the
next panel in the second cycle of process. The die bonding machine
will repeat these steps until all of the PCB panels in the input
magazine are processed. This process step may repeat again for the
same panel for stack die products that may require to stacks more
than one layer of memory die. FIG. 9(B) is a top perspective views
showing PCB 111-1 of PCB panel 300(t2) after the die bonding
process is completed.
FIG. 10(A) is a perspective view depicting a wire bonding process
utilized to connect the IC dies 131, 135 and 137 to corresponding
contact pads 119-4, 119-5 and 119-6, respectively, according to
block 245 of FIG. 5. The wire bonding process proceeds as follows.
Once a full magazine of PCB panels 300(t2) (see FIG. 9(B)) has
completed the die bonding operation, an operator transports the PCB
panels 300(t2) to a nearby wire bonder (WB) machine, and loads the
PCB panels 300(t2) onto the magazine input rack of the WB machine.
The WB machine is pre-prepared with the correct program to process
this specific USB device. The coordinates of all the ICs, pads
119-4, 119-5 and 119-6 and PCB gold fingers were previously
determined and programmed on the WB machine. After the PCB panel
with the attached dies is loaded at the WB bonding area, the
operator commands the WB machine to use optical vision to recognize
the location of the first wire bond pin of the first memory die of
the first PCB on the panel. Once the first pin is set correctly,
the WB machine can carry out the whole wire bonding process for the
rest of the panels of the same product type automatically. For
multiple flash layer stack dies, the PCB panels may be returned to
the WB machine to repeat wire bonding process for the second stack.
FIG. 10(B) is a top perspective views showing PCB panel 300(t3)
after the wire bonding process is completed.
FIGS. 11(A) and 11(B) are simplified cross-sectional side views
depicting a molding process for forming a molded housing layer over
PCB panel 300(t3) according to block 250 of FIG. 5. As indicated in
FIG. 11(A), after the wire bonding process is completed, USB panel
300(t3) is loaded into a mold machine 450 including a cover plate
452 that mounts onto lower surface 116 of PCB panel 300(t3), and
defines a chamber 456 that is disposed over the IC chips, wire
bonds and passive components that are mounted on lower surface 116
of each PCB. Note that no molding material is applied to upper
surface 118. Transfer molding is prefer here due to the high
accuracy of transfer molding tooling and low cycle time. The
molding material in the form of pellet is preheated and loaded into
a pot or chamber (not shown). As depicted in FIG. 11(B), a plunger
(not shown) is then used to force the material from the pot through
channels known as a spruce and runner system into the mold cavity
456, causing the molten (e.g., plastic) material to form molded
casings 150 over each PCB that encapsulates all the IC chips and
components, and to cover all the exposed areas of upper surface
116. The mold remains closed as the material is inserted and filled
up all vacant in cavity 456. During the process, the walls of cover
plate 452 are heated to a temperature above the melting point of
the mold material, which facilitates a faster flow of material
through cavity 456. Mold machine 450 remains closed until a curing
reaction within the molding material is complete. A cooling down
cycle follows the injection process, and the molding materials of
molded casings 150 start to solidify and harden. Ejector pins push
PCB panel 300(t4) (shown in FIG. 12) from the mold machine once
molded casings 150 has hardened sufficiently.
Referring again to blocks 260-268 of FIG. 5, the fabrication of
molded lead-frame connectors (e.g., connector 170; see FIG. 3(A))
is now described with reference to FIGS. 13(A) through 14(B). Each
lead frame begins as a continuous stripe of copper or alloy sheet
metal (block 260; FIG. 5) that is then cut and down set using known
techniques to produce lead frame panel 500(t0), which is shown in
FIG. 13(A). Lead frame panel 500(t0) includes ten lead frames 510
arranged in two rows of five. As indicated in FIG. 13(B), each lead
frame 510 includes a four-sided metal frame 520 surrounding a
central opening 525, with five leads 572 and eight 575 extending
from opposite portions of metal frame 520 into central region 525.
Note that the cut and down set process is controlled using known
techniques to produce bumps 172C and 175C in each of the leads, and
also to provide the raised step-like regions such as those
described above at the free ends of each lead. The leads 572 and
575 are then electro-plated with a thin layer of nickel and gold
for preventing corrosion and ensuring good (low) contact resistance
for providing good electrical contact. Round index holes 530 are
provided during the cutting process for machine recognition and
alignment purposes for down stream processes. Metal frame 530
serves to hold leads contactor pins in place during the subsequent
plastic molding process.
Referring to FIGS. 14(A) and 14(B), lead frame panel 500(t0) is
then loaded into a transfer mold machine similar to that described
above with reference to FIGS. 11(A) and 11(B) such that the free
ends of each lead is received inside the molding chamber and is
encapsulated into the thermo set plastic material, thereby forming
lead frame panel 500(t1) having molded bodies 171 in the middle
section of each lead frame 510. Note that the base portion of each
lead including its bent portion (e.g., portion 172C of each lead
575) remains outside of the molding chamber, and as such extends
form molded body 171. Molded lead frame panel 500(t1) is then moved
to a singulation station to have the pins and the metal frames 510
separated along cut lines CL on each row of the panel. The
resulting individual molded lead-frame connectors 170 are described
above with reference to FIGS. 3(A) and 4(A).
FIGS. 15(A) and 15(B) show the subsequent process, in accordance
with block 270 of FIG. 5, of mounting molded lead-frame connectors
170 (e.g., connector 170-1) onto corresponding PCBs (e.g., PCB
111-1) of PCB panel 300(t4) using SMT techniques, which has been
processed as described above with reference to FIG. 12. During this
SMT mounting process, lead-free solder paste portions 522 and 525
are printed onto each of contact pads 122 and 125, respectively, of
each PCB on panel 300(t4) using a conventional stencil printer
machine. A pick-and-place machine (not shown) then picks up and
mounts lead-frame connector 170-1 on PCB 111-1 with precise
alignment such that the associated contact pad 172A of each contact
pin 172 is mounted onto a corresponding contact pad 122, and such
that the associated contact pad 175A of each pin 175 is mounted
onto a corresponding contact pad 125. The surface mount process is
then repeated for each PCB 111 of panel 300(t4). The panel with
lead-frame connectors mounted thereon is then send through a
standard IR-reflow oven, which has the proper temperature of each
temperature zone set correctly prior to the start of the process,
to complete the SMT process. FIG. 15(B) shows PCB panel 300(t5)
including subassemblies 101A, including sub-assembly 101A-1 having
lead-frame connector 170-1 mounted on PCB 111-1.
FIG. 16 is simplified cross-sectional side view depicting a
singulation process according to block 275 of FIG. 5 that is used
to separate PCB panel 300(t5) into individual sub-assemblies 101A.
PCB panel 300(t5) is loaded into a saw machine (not shown) that is
pre-programmed with a singulation routine that includes
predetermined cut locations. The saw blade is aligned to the first
cut line (e.g., end cut line 311-1) as a starting point by the
operator. The coordinates of the first position are stored in the
memory of the saw machine. The saw machine then automatically
proceeds to cut up (singulate) the USB pane 300(t5), for example,
successively along cut lines 311-1, 341-1, 341-2, and 311-2, and
then along the side cut lines and PCB cut lines (see FIG. 5(A)) to
form individual sub-assemblies 101A, which are shown and described
above with reference to FIGS. 3(A) and 3(B), according to the
pre-programmed singulation routine.
FIG. 17 is an exploded perspective view showing an extended
Universal-Serial-Bus (USB) dual-personality card reader 101-1
according to a first specific embodiment that includes sub-assembly
101A (described above), an external housing 180-1, and a metal USB
connector head cover (plug shell) 620. Housing 180-1 is produced or
procured in accordance with block 280 of FIG. 5, and sub-assembly
101A is mounted inside housing 180-1 in accordance with block 290
of FIG. 5. Both housing 180-1 and the process of mounting
sub-assembly 101A inside housing 180-1 are described in the
following paragraphs with reference to FIGS. 17-22.
Housing 180-1 includes an upper top cover housing portion 610A and
a lower main body housing portion 610B that are pre-molded plastic
structures formed using known techniques. The term "pre-molded" is
used herein to indicate that top cover 610A and lower housing
portion 610B are an integral molded structures formed during
separate (e.g., injection) plastic molding processes that are
performed prior to assembly.
Referring to the upper portion of FIG. 17, top cover 610A includes
an upper wall 611A, opposing side walls 613A1 and 613A2, a rear
wall 614A1 defining a slot opening 614A1-A that communicated with
an internal chamber (slot) 187-1, and a front surface 614A2.
Locking grooves 617A are defined on front surface 614A2 of upper
wall 611A and side walls 613A1 and 613A2 for receiving tabs 627
extending from head cover 620. Although not shown, lower surfaces
of side walls 613A1 and 613A2 and rear wall 614A1 define grooves
for snap-coupling top cover 610A to lower housing portion 610B in
the manner described below.
Referring to the lower portion of FIG. 17, lower housing portion
610B includes a lower wall 611B, opposing side walls including wide
rear portions 613B11 and 613B21 and opposing narrow front portions
613B12 and 613B22, a rear wall 614B1 and a front wall 614B2. Lower
wall 611B, side walls 613B11, 613B21, 613B12 and 613B22, rear wall
614B1 and front wall 614B2 define a trough 612 for receiving
sub-assembly 101A. A raised collar structure 615 is integrally
molded to side walls 613B11 and 613B21, and extends between the
opposing side wall over trough 612. Locking ribs 616 extend upward
from upper edge surfaces of side wall portions 613B11 and 613B21
and rear wall 614B1, and serve to snap-couple top cover 610A to
lower housing portion 610B as described below. Locking grooves 617B
are defined on front surface 614B1 of side wall portions 613B11 and
613B21 for receiving corresponding tabs 627 extending from head
cover 620. Notches 618 are defined on side wall portions 613B11 and
613B21 for receiving corresponding bumps 628 extending from side
walls 623-1 an 623-2 of head cover 620. Protrusions 619 extend from
the front ends of side wall portions 613B11 and 613B21 for engaging
corresponding notches 629 defined in side walls 623-1 an 623-2 of
head cover 620.
Head cover 620 is a folded metal sheet that extends over and
becomes coupled to lower housing portion 610B in the manner
described below. Head cover includes opposing upper and lower walls
621A and 621B that are held by opposing side walls 623-1 and 623-2,
and are sized to slip tightly over the front end of lower housing
portion 610B (i.e., such that lower wall 621B is disposed under
lower wall 611B, and a rear portion of upper wall 621A is mounted
on the upper surface of raised collar structure 615). Upper wall
621A includes openings and markings that are consistent with
standard USB plug shell structures. Side walls 623-1 and 623-2
include bumps 628 and notches 629 whose purpose is described below.
In addition, tabs 627 extend from a rear edge of upper and lower
walls 621A and 621B and side walls 623-1 and 623-2.
The assembly of card reader 101-1 is now described with reference
to FIGS. 18(A) to 22(C). Referring to FIG. 18(A), sub-assembly 101A
is inserted into lower housing 610B by tilting and sliding
sub-assembly 101A into recess 612 through the opening defined by
raised collar structure 615. When fully inserted, as shown in FIG.
18(B), sub-assembly 101A settles snuggly between side walls 613B11,
613B21, 613B21 and 613B22, and between rear wall 614B1 and front
wall 614B2, with USB contacts 121 disposed adjacent to front wall
614B2. Note that connector 170 is positioned relative to raised
collar structure 615 such that pins 175 are disposed in front of
collar structure 615, and pins 172 are disposed behind collar
structure 615. Referring to FIGS. 19(A) and 19(B), metal USB
connector head cover 620 is then slid over the front end of lower
housing portion 610B and secured by way of tabs 627, which are
received in slots 617 disposed on front surface 615B1 of side wall
portions 613B11 and 613B21. When fully assembled, bumps 628 are
resiliently engaged into notches 618, and protrusions 619 are
received in notches 629 to secure head cover 620 onto lower housing
portion 610B, which further serve to secure head cover 620 to lower
housing portion 610B. Note that upper wall 621A forms a gap G that
allows access to USB contacts 121 and pins 177 during subsequent
operation. Finally, as shown in FIG. 20(A), top cover 610A is
lowered at an angle onto the sub-assembly of FIG. 19(B) such that
slots 617A receive tabs 627. Then, the rear end of top cover 610A
is pressed downward toward lower housing portion 610B, which causes
locking ribs 616 to engage (i.e., snap-couple) with corresponding
grooves (now shown) formed on lower surfaces of top cover 610A. The
thus completed card reader 101-1 is shown in top and bottom views
in FIGS. 20(B) and 20(C), respectively.
Referring to block 295 located at the bottom of FIG. 5, a final
procedure in the manufacturing method of the present invention
involves testing, optional marking, packing and shipping the
individual card reader devices. Visually or/and electrically test
rejects are removed from the good population as defective rejects.
The good card readers are then packed into custom made boxes which
are specified by customers. The final packed products will ship out
to customers following correct procedures with necessary
documents.
FIGS. 21, 22(A) and 22(B) depict the manual insertion of micro-SD
card 50 into card reader 101-1, which facilitates communication
between micro-SD card 50 and a host system (e.g., host system 105,
see FIG. 2). As indicated in FIGS. 21 and 22(A), micro-SD card 50
is inserted through opening 614B1-1 into slot 187-1 until, as
indicated in FIG. 22(B), contacts 55 of micro-SD card 50
resiliently compress the curved portions of rear-facing contact
structures 175, thereby facilitating communications between
micro-SD card 50 and PCBA 110 (when power is applied) by way of USB
contacts 121 and forward-facing contact structures 172. As
indicated in FIG. 21, top cover 610A includes a curved recess R for
facilitating removal of micro-SD card 50 after completion of a
communication session.
In addition to providing functions as a micro-SD card reader, card
readers formed in accordance with the present invention may be
modified to serve both as "standard" USB devices and as micro-SD
card readers, thus enhancing their functionality. As suggested in
the above example, overall manufacturing costs are reduced by
utilizing unpackaged controller and flash memory dies (i.e., by
eliminating the packaging costs associated with SMT-ready
controller and flash memory devices). A dual dual-purpose
controller is provided (as described below with reference to FIG.
23) to facilitate dual-purpose operation. In addition, space saving
arrangements are described below with reference to FIGS. 24 and 25
for providing the needed significant memory capacity for use in the
USB device mode (i.e., without requiring the insertion of a
micro-SD card) without increasing the overall size of the resulting
card reader.
FIG. 23 is a block diagram showing a simplified dual-purpose
controller 130-2 according to another embodiment of the present
invention. CPU 710 communications with a dual-personality
transceiver 720 and a card reader control interface 730 by way of
an internal bus 740. Dual-personality transceiver 720 operates in a
manner similar to that described above with reference to host
system 105 (FIG. 2) to communicate with both standard USB contact
pads 121 and extended purpose contact structures 172 in order to
communicate with a host system, e.g., by way of socket 190 (see
FIG. 2). Card reader control interface 730 communicates in the
manner described above to communicate with a micro-SD card by way
of extended purpose contact structures 175. Note that controller
130-2 includes a memory controller 750 for controlling read/write
operations to flash memory circuits that are part of the PCBA
hosting dual-purpose controller 130-2, thereby facilitating the
dual functions (i.e., card reader and USB-type device) that are
described above.
FIG. 24 is simplified cross-sectional side view showing a
stacked-memory PCBA 110-2 in which dual-purpose controller 130-2
accesses a first flash memory chip 535-1 and a second flash memory
chip 535-2. First flash memory chip 535-1 is mounted on an upper
surface 118 of a PCB 111-2 and connected by first wire bonds 560-1
to PCB 111-2 in the manner described above. Because the IC die
height (thickness) D is much smaller than packaged flash memory
devices, and because the thickness T1 of USB device 500 is set, for
example, at 2.0 mm to assure a snug fit of the card reader inside a
female USB socket (e.g., socket 190, shown in FIG. 1(A)), the
present invention facilitates a stacked memory arrangement in which
second flash memory die 535-2 is mounted on first flash memory die
535-1 and connected to PCB 111-2 by way of second wire bonds 560-2.
In an alternative embodiment (not shown), second flash memory die
535-2 may be connected to contacts provided on first flash memory
die 535-1 by associated wire bonds. This stacked memory arrangement
greatly increases memory capacity of the card readers without
increasing the footprint (i.e., thickness T1, length and width) of
PCBA 110-2. PCBA 110-2 is then processed and assembled as described
above to produce a corresponding completed card reader device.
FIG. 25 is simplified cross-sectional side view showing a PCBA
110-3 including stacked-memory according to another embodiment of
the present invention. PCBA 110-3 is distinguished over the
previous embodiments in that, instead of separate controller and
flash memory chips, PCBA 110-3 utilizes a single-chip dual-purpose
controller/flash die 630 that is connected to a PCB 111-3 by way of
wire bonds 660 in the manner described above, and is characterized
in that single-chip dual-purpose controller/flash die 630 includes
both a dual-purpose controller circuit and one or more flash block
mass storage circuits that are interconnected by a bus.
FIG. 26 is an exploded perspective view showing an extended
Universal-Serial-Bus (USB) dual-personality card reader 101-2
according to another specific embodiment that includes sub-assembly
101A (described above), an external housing 180-2, and a metal USB
connector head cover (plug shell) 830. Housing 180-2 is produced or
procured in accordance with block 280 of FIG. 5, and sub-assembly
101A is mounted inside housing 180-2 in accordance with block 290
of FIG. 5.
Housing 180-2 includes a main housing portion 810 and a tray
portion 820 that are pre-molded plastic structures. Main housing
portion 810 includes an upper wall 811-1, a lower wall 811-2,
opposing side walls 813-1 and 813-2, a rear wall 814-1 defining a
slot opening 814-1A (shown in FIG. 27(A)) that communicates with an
internal chamber (slot) 187-2, and a front wall 814-2 defining a
front opening 814-2A that also communicates with slot 187-2. Tray
820 includes a bottom wall 821, side walls 823-1 and 823-2, and a
front wall 824. Rear protrusions 827 are located at the back of
lower wall 821 for securing tray 820 inside head cover 830, and
front protrusions 829.
Metal head cover 830 includes an upper wall 831-1, a bottom wall
831-2, and side walls 833-1 and 833-2. A pair of connecting flanges
836 extend from the back edges of side walls 833-1 and 833-2, and a
pair of notches 829 are defined in the front edges of side walls
833-1 and 833-2.
During assembly, tray 820 is slid into head cover 830 through its
rear opening until protrusions 829 are snap-coupled into notches
839. Sub-assembly 101A is then inserted into main housing portion
810 through front opening 815, and the tray/head cover assembly is
then mounted over the front end of sub-assembly 101A and pushed
inward such that the front end of sub-assembly 101A is pressed
backward by front wall 824. When the tray/head cover assembly is
fully inserted, the rear end of sub-assembly 101A is pressed
against rear wall 814-1 of main housing portion 810, and flanges
836 become snap-coupled and held by corresponding structures (not
shown) disposed behind front wall 814-2. The fully assembled card
reader 101-2 is shown in FIGS. 27(A) and 27(B).
FIG. 28 is an exploded perspective view showing an extended
Universal-Serial-Bus (USB) dual-personality card reader 101-3
according to another specific embodiment that includes sub-assembly
101A (described above) and an external housing 180-3 that includes
a main housing portion 910 and a tray portion 920 that are
pre-molded plastic structures. Main housing portion 910 includes an
upper wall 911-1, a lower wall 911-2, opposing side walls 913-1 and
913-2, a rear wall 914-1 defining a slot opening 914-1A (shown in
FIG. 29(A)) that communicates with an internal chamber (slot)
187-3. Disposed at the front end of main housing portion 910 is an
integrally formed plastic head cover 930 that serves the purpose of
metal head cover 830 (described above), but is less expensive in
that it is integrally molded with main housing portion 910, and
removes at least one assembly step. Tray 920 is similar to tray 820
(described above) and serves a similar purpose.
During assembly, sub-assembly 101A is inserted into main housing
portion 910 through front opening 915, and then the rear end of
tray 920 is squeezed and slid into front opening 915 until front
protrusions 929 are snap-coupled into notches 919. When the tray
920 is fully inserted, the rear end of sub-assembly 101A is pressed
against rear wall 914-1 of main housing portion 910, and flanges
936 become snap-coupled and held by shoulder structures 914-2
formed at the rear end of plastic head cover 930. The fully
assembled card reader 101-3 is shown in FIGS. 29(A) and 29(B).
FIG. 30 is an exploded perspective view showing a "low-profile"
extended Universal-Serial-Bus (USB) dual-personality card reader
101-4 according to another specific embodiment that includes
sub-assembly 101A (described above) and an external housing 180-4
that includes a main housing portion 1010 and a bottom cover
portion 1020 that are pre-molded plastic structures. Main housing
portion 1010 includes an upper wall 1011-1, opposing side walls
1013-1 and 1013-2, a rear wall 1014-1 defining a slot opening
1014-1A (shown in FIG. 31(A)) that communicates with an internal
chamber (slot) 187-4. A front tray structure 1030 is integrally
formed and extends from side walls 1013-1, and defines a trough
1012 for holding a front end of sub-assembly 101A. Main housing
portion 1010 also includes a bottom opening 1011-1A (viewed through
trough 1012).
During assembly, sub-assembly 101A is inserted into main housing
portion 1010 through bottom opening 1011-1A such that the front end
of sub-assembly 101A is received in tray 1012, and then the rear
end of sub-assembly 101A is pushed into the space below upper wall
1011-1. Bottom cover 1020 is then secured over lower opening
1011-1A using ultrasonic welding. The fully assembled card reader
101-4 is shown in FIGS. 31(A) and 31(B).
Although the present invention has been described with respect to
certain specific embodiments, it will be clear to those skilled in
the art that the inventive features of the present invention are
applicable to other embodiments as well, all of which are intended
to fall within the scope of the present invention. For example,
although the present invention is described above as supporting
micro-SD cards, the disclosed embodiments may be altered using
known techniques to serve as card readers for other types of memory
devices, including standard SD cards, MMC cards, Mini-SD cards,
Micro-SD cards and memory stick cards. In addition, the socket and
related rear-facing pins may be selected to connect with two or
more of the memory device types (e.g., SD and MMC).
* * * * *